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I have a few concerns - I was told that with the variable speed I will hardly ever hear the fan on. When the a/c kicks on, the low fan is on at first then immeditely ramps into a louder fan. Runs for 10 minutes or so at that speed and right before it shuts off it ramps even louder then shuts off. I don't understand why my motor would run so high if my inside temp = set temp. Shouldn't the low fan run most of the time since the desired temp is already achieved?

I also don't understand why the motor blows really hard right before shut down. That makes no sense to me. I would think I'm using more energy for this. I purchased this product to save energy!

Also, I'm confused on how I should be running the fan - On, Auto or Circ. I live in AZ where it was 110 degrees yesterday. I'm hearing conflicting stories on most efficient way to run the fan with the units I've purchased.

2800 sq ft of living area. I originally had 3.5 tons for both units and I was told that 4 tons with variable speed motors would not be overkill in my house. I was told this repeatedly by many dealers. The thermostats are Honeywell Vision Pro 8000s.

I live in Scottsdale, AZ so it is pretty hot here. I had 2 3.5 ton units for my house and I was paying over $400/month in electricity while keeping both units at 87 degrees from 8AM to 2 PM, then 85 degrees after 2 PM. My old units were 26 years old and needed changing.
the 4 ton variable speed units I purchased are 2 stage units. What I don't understand is why the fan blows mostly loud during it's approxmate 10-12 minute run. With a variable speed fan/motor, isn't it supposed to run at a slower speed to be more efficient? I'm just wondering if this is an installer issue because I was told the fan would run at slow speed most of the time, which is not the case.